How can i make flashing graphics?

Great but expensive:

photoshop and/or fireworks

Free:

the GIMP

Others:

flash depending on the application can work

If you have access to photoshop or fireworks use them if not the GIMP can work but I personally prefer the adobe product line.

Edit: you will be wanting to make .gif files by the way

I highly recommend iPixSoft Flash Slideshow Creator, it can help you to make flash slideshow,flash banner, slideshow album, photo gallery for web design.

In addition, its official website provides step by step tutorial such as

Make a Graduation Slideshow Album with Music

http://www.ipixsoft.com/flash-gallery-tutorial/gra...

Make a Christmas Ornaments Photo Presentation with Hyperlink

http://www.ipixsoft.com/flash-gallery-tutorial/chr...

Make a Christmas Photo Album with Music

http://www.ipixsoft.com/flash-slideshow-tutorial/c...

Make a Flash Slideshow with Music

http://www.ipixsoft.com/flash-slideshow-tutorial.h...

Make a flash banner for webpage with hyperlink

http://www.ipixsoft.com/flash-banner-tutorial.html

Make a Valentine's Day Slideshow with Music

http://www.ipixsoft.com/flash-gallery-tutorial/van...

for the site, u must use Macromedia Flash and After effect it's give something good effect